Tension device for shears.



G. M. GRIDER. TENSION DEVICE FOR 'sEEAEs.

APPLICATION FILED MAY 28, 1909.

95 1 ,23 6. Patented Mar. 8, 1910.

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UNITED STATES PATENT OFFICE.

GEORGE M. CRIDER, 0F MARION, KENTUCKY.

TENSION DEVICE FOR SHEARS.

To all whom it may concern:

Be it known that I, GEORGE M. CRIDER, a citizen of the United States,residing at Marion, in the county of Crittenden and State of Kentucky,have invented certain new and useful Improvements in Tension Devices forShears, of which the following is a specification.

This invention comprehends certain new and useful improvements in shearsand like cutting instruments and relates more particularly to animproved tension device through the instrumentality of which the bladesof the shears are held forcibly together, so as to cut more effectuallyand render the blades self-sharpening, the device being susceptible ofready adjustment and possessing certain other advantages that render itparticularly attractive.

Vith this and other objects in view that will more fully appear as thedescription proceeds, the invention consists in certain constructionsand arrangements of the parts that I shall hereinafter fully describeand then point out the novel features in the appended claims.

F or a full understanding of the invention and the merits thereof andalso to acquire a knowledge of the details of construction, reference isto be had to the following description and accompanying drawing, inwhich:

Figure 1 is a plan view of a pair of shears embodying the improvementsof my invention; Fig. 2 is a transverse section showing the screw backedoil and the wedge in an inoperative position; Fig. 3 is a similar viewwith the wedge inserted beneath the washer; and, Fig. 4 is a plan viewof a modification hereinafter specifically described.

Corresponding and like parts are referred to in the followingdescription and indicated in all the views of the drawing by the samereference characters.

My improved tension device is illustrated as applied to an ordinary pairof shears consisting of the blades 1 and 2 which are of conventionalform and are connected together by means of a pivot bolt 3 that ispassed through registering pivot openings 4. Interposed between the headof the pivot bolt and the adjacent blade, designated 1, is a hollowcylindrical washer 5 that is accommodated in an enlarged portion 6 ofthe corresponding pivot opening. The

Specification of Letters Patent.

Application filed May 28, 1909.

Patented Mar. 8, 1910. Serial No. 498,889.

washer is adapted to rest upon an outwardly facing interior shoulder 7provided by the enlargement 6. The blade 1 is also formed with atransverse opening 8 which opens outwardly through a side edge thereofand leads into the enlarged portion 6. This opening is interiorlythreaded and designed for the reception of a screw 9, the latter havingits extremity gradually tapered to constitute a wedge 10 which isarranged to be inserted beneath the washer to force the same outwardlyagainst the head of the pivot bolt, whereby to exert tension upon thepivot bolt and increase the tension between the blades 1 and 2.Attention is particularly directed to the fact that the opening 8 is sosituated so as to be bisected longitudinally by the plane of theshoulder 7, the portion of the opening disposed below the planeregistering with a groove 11 formed in the shoulder. By virtue of suchan arrangement it is to be noted that the point of the wedge issupported substantially in the plane of the shoulder, thus insuring thewedge assuming an operative position beneath the washer when the screwis advanced.

From the foregoing description in connection with the accompanyingdrawing, it will be apparent that I have provided an improved tensiondevice which holds the blades of the shears forcibly together to renderthem more eflicient and make them self-sharpening; which admits of thetension between the blades being expeditiously regulated by merelyadjusting the screw in the blade; which is very compact and embodies toa marked degree the characteristics of simplicity and durability; andwhich consists of comparatively few parts that may be easily and cheaplymanufactured, so as to be capable of being applied to the shears withoutmaterially increasing their cost.

' It is to be understood that I do not limit myself to placing the screwat the side edge of the blade, but, if desired, may arrange the screwlongitudinally, as illustrated in Fig. 4:, wherein the screw enters theblade in the rear of the pivot bolt at the point where the blade isoifset for the handle. In this instance the projecting head of the screwis located between the handle, so as to be entirely out of the way andbe prevented from possibly catching on the material to be cut.

Having thus described the invention what is claimed as new is:

1. The combination of a cutting instrument embodying blades formed withregistering pivot openings, one of which is enlarged to provide aninterior shoulder, a pivot pin passed through the openings, a memberencircling the pivot pin and accommodated in the enlarged portion, andmeans for forcing the member away from the shoulder to exert tension onthe pivot pin.

2. The combination of a cutting instrument embodying blades formed withregistering pivot openings, one of which has an interior shoulder, apivot pin passed through the openings, 21 member encircling the pivotpin in proximity to said shoulder, and a screw working in one of theblades and. provided with a terminal wedge adapted to be projected intosaid pivot opening between the shoulder and the member to exert tensionon the pivot pin.

3. The combination with a cut-ting instrument embodying blades formedwith registering pivot openings, and a pivot pin inserted through theopenings, of a tension device embodying a washer mounted on the pivotpin and interposed between the head thereof and the adjacent blade, oneof the pivot openings being enlarged to accommodate the washer, and awedge inserted beneath the washer to force the same outwardly and exerttension on the pivot pin.

l. The combination with a cutting instrument embodying blades formedwith registering pivot openings, and a pivot pin inserted through theopenings, of a tension device embodying a washer mounted. on the pivotpin and interposed between the head thereof and the adjacent blade, oneof the pivot openings being enlarged to accommodate the washer, the saidadjacent blade be ing formed with a threaded opening lead ing into theenlarged portion, and a screw working in the threaded opening andprovided at its extremity with a wedge adapted to be projected into theenlargement and inserted beneath the washer to exert tension on thepivot pin.

In testimony whereof I aflix my signature in presence of two witnesses.

GEORGE M. CRIDER. \Vitnesses H. K. \Vooos, L. J. RANDOLPH.

